BY Chapter 9
The genetic code consists of __ possible codons that specify amino acids.
64
Types of Mutations:
Base pair substitutions, insertions, deletions
T or F: 1 tRNA comes during elongation.
False! 2
If a mutation arises in a _____, it may be passed on to offspring.
Gamete
A unit of information for a heritable trait
Gene
A multistep process including transcription and translation by which genetic information encoded by a gene is converted into a structural or functional part of a cell
Gene Expression
A linear stretch of DNA that specifies the sequence of amino acids in a polypeptide is called a(n)
Gene.
3 stages of translation:
Initiation, Elongation, Termination
In correct order, the three stages of translation are...
Initiation, chain elongation, and termination.
Frameshift Mutations:
Insertion and Deletion
Non - coding portions, ___, are cut out.
Introns
The portion of the DNA molecule that is not translated and is a noncoding portion of DNA is composed of...
Introns.
Termination:
Release of the finished polypeptide
What is the site of protein synthesis?
Ribosomes
rRNA:
Major component of ribosomes upon which polypeptides are assembled
Elongation:
Makes the chain of polypeptides
The form of RNA that carries the code from DNA to the site of protein assembly is called:
Messenger RNA
__________ molecules carry protein-assembly instructions from the nucleus to the cytoplasm.
Messenger RNA
What are the three classes of RNA?
Messenger RNA, Ribosomal RNA, and Transfer RNA
Initiation:
The ribosomal subunits join around the mRNA strand and the mRNA and tRNA undergo base pair matching
A gene mutation:
is a change in the nucleotide sequence of DNA, may occur spontaneously, may occur as a result of environmental agents
Translation:
mRNA leaves the nucleus and finds a ribosome. mRNA is decoded into a sequence of amino acids, resulting in a polypeptide chain that folds into a protein.
Transcription...
occurs during the synthesis of any type of RNA from a DNA template.
Transcription starts at a region of DNA called a(n)
promoter.
If the DNA triplets are ATG-CGT, the mRNA codons are...
UAC-GCA.
Which substance is found in RNA but not in DNA?
Uracil
The RNA molecule is made up of how many strands?
1
How many codons of the code serve to stop protein synthesis?
3
The genetic code is made up of units consisting of how many nucleotides?
3
The end of RNA that is not capped contains what?
A "Poly A" signal that helps with stopping translation
Unlike DNA Replication, in Transcription...
A single strand is produced Only a small stretch is used as a template RNA Polymerase catalyzes rather than DNA Polymerase
What is always the "start" codon?
AUG
Uracil will pair with _.
Adenine
Each codon stands for a specific ___.
Amino Acid
Each gene is a linear stretch of DNA that codes for the specific assembly of ___ into a ___
Amino Acids; Protein
Before leaving the nucleus, the RNA molecule:
Becomes capped, is released from the STOP signal, is stripped of its introns
Before RNA leaves the nucleus, one end is ___.
Capped with a specific signal that is involved in translation.
mRNA:
Carries protein building instruction from DNA
DNA is transcribed in three letter sequences known as ___.
Codons
Anticodon:
Complementary to a mRNA codon; tRNA has them
Where does translation occur?
Cytoplasm
Transcription:
DNA is copied into a new code to produce mRNA. It occurs in the nucleus. mRNA moves into the cytoplasm. Synthesizes new molecules by base-pairing.
tRNA:
Delivers the appropriate amino acids to the ribosome for assembly into a protein
Coding portions, ___, are left in.
Exons
Which of the following agents is a known cause of mutations?
Nonionizing radiation, ionizing radiation, and chemicals.
RNA transcription occurs in the:
Nucleus
Transcription begins when RNA Polymerase binds to a ____.
Promoter Region
____ transcribes DNA into RNA.
RNA Polymerase
Two steps that create all proteins:
Transcription and Translation
T or F: Like DNA replication, nucleotides are added in 5' to 3' direction in transcription.
True
In RNA, T is replaced with __.
U
Frameshift mutations may involve...
addition or deletion of one or more base pairs.
Which of the following carries amino acids to ribosomes, where amino acids are linked into the primary structure of a polypeptide?
tRNA